We are having problems with ammonia screw compressors failing when the vibration data appears to be OK. If on a 3600 RPM compressor the lobe pass frequecy is 14,400 cpm (4X turning speed) then 3X this would be 43,200 cpm. We usually have no way of knowing what bearings are in the compressors but...
Thanks for your response. I do have one more question. We monitor these ammonia screw compressore 4 times a year for a certain company. While it is pretty easy to determine the lobe pass frequency in these units, we have no access to the bearing model or manufacturer. Our customers do not know...
I have been told that the only way to monitor vibration on an ammonia screw compressor was to collect data at 100% and 0% loads. What do you thing about this? Also, what is the best fmax to for collecting data at thes loads?
